Auth bypass in Cisa Malcolm
CVE-2026-90450
The application's role-authorization lookup defaults to granting access when a request handler's name is not present in its table of role requirements, rather than defaulting to deny. Any request handler that is not explicitly registered in this table is reachable by any authenticated user regardless of their assigned role, and any newly added handler is fail-open by default until explicitly added to the table.
Vulnerability class: Broken Access Control
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.
EPSS exploit prediction
EPSS: 0.002 (7.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 7th percentile — 7.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.002 · change: -0.002
Affected products
Weakness classification (CWE)
References
- raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/OT/white/2026/icsa-26… (vendor-advisory, government-resource)
- www.cisa.gov/news-events/ics-advisories/icsa-26-254-01
Frequently asked questions
- What is CVE-2026-90450?
- CVE-2026-90450 is a medium-severity vulnerability in Cisa Malcolm, classified under Incorrect Authorization. CVSS score: 4.3/10. Published 2026-09-11.
- How severe is CVE-2026-90450?
- Medium severity. CVSS v3 base score is 4.3 out of 10.